The Pediatric Oncology Program at the University of Wisconsin in Madison is a founding member of CCSG. Over the past five year, we have entered almost 32 patients/year on CCSG therapeutic trials, contributing about 1.5% of Group entries. In the 20 months, between 1/1/86 and 8/31/87, 15/22 "new" patients with leukemia (68%) and 32/66 "new" patients with solid tumors (48%) were entered on Group therapeutic trials. We have contributed about 3% of entries to Group Epidemiology and Special studies. Our record for data submission has been excellent. We hope to improve our accruals 1) as new studies open for bone marrow transplant, brain tumor, and late effects; 2) as we improve communication with area physicians; and 3) with the addition of Dr. Timothy Kinsella in Radiation Oncology as Chairman of the Department of Human Oncology and of Dr. John Heiner to the Department of Orthopedic Surgery. The principal contribution of the Pediatric Oncology Program at UW will likely remain in the area of scientific leadership. Drs. michael Trigg and Jonathan Finlay have left the program. Dr. Paul Gaynon has arrived. He has been active in the Group for nine years and will serve as principal investigator. He has had major responsibility for writing 7 protocols and has served as chairman or co-chairman for CCG-085, CCG- 093, CCG-99, CCG-106, CCG-192P, CCG-193P, CCG-321P and CCG-S70. He serves as Coordinator for Front Line ALL trials on the Leukemia Strategy Group and on the New Agents Steering and Computer Committees. Dr. Paul Sondel has been a leader in the investigation of biological therapeutics - especially IL-2 - both in the UW Clinical Cancer Center and in the Group. He serves in the Immunocology Committee and will chair CCG-8609, the planned phase I trial of IL-2. He has co-directed the UW ALL Immunophenotype Resource Laboratory for the Group and is establishing a CCSG IL-2/Biotherapy Resource Laboratory here. Details are provided in the Group Chairman's grant.